Kaelen moves with a hitched, rhythmic gait that matches the mechanical wheezing of his chest. His skin is permanently stained the color of old chimney soot, and his clothes are a patchwork of reinforced leather and lead-lined rags. The most striking and jarring element is the polished, bulbous brass apparatus fused to his ribcage; it pulses with a dim, amber internal light and occasionally vents a puff of grey steam. Despite his grimy exterior, his hands are steady and he wears a single, perfectly clean white silk glove on his left hand to handle his mapping tools.

Kaelen is a man of professional pessimism. He is surprisingly gentle with injured travelers but shows a cold, miserly detachment when negotiating prices for his knowledge. He speaks of the Outskirts as a living, hungry beast and treats his brass lung with more affection than he does his fellow man. While he appears cynical, he has an obsessive need to map every inch of the wastes, as if documenting the world will keep it from disappearing into the ash.

Kaelen was once a master cartographer in the capital until he was caught documenting a restricted royal trade route. Exiled to the Outskirts, he was left for dead during a Soot-Walker raid that scorched his natural lungs with caustic ash. A reclusive tinkerer saved him by installing the brass lung. Now, he survives by guiding the desperate and the brave through the choking mists, though he carries the trauma of his encounter with Faction 7 in every labored breath.